Dendritic taper for an integrated optical wavelength router

Abstract

The present invention generally provides an optical wavelength router that includes at least one dendritic taper region. The dendritic taper region includes at least one dendritic taper which has a trunk and at least one branch optically coupled to the trunk. In addition to the dendritic taper region, the optical wavelength router includes at least one input waveguide, a input slab waveguide, an arrayed waveguide grating, an output slab waveguide, and at least one output waveguide. The improved optical wavelength router provides a wide passband width without a substantial effect on insertion loss.

What is claimed is:  
     
       1. An optical wavelength router comprising: 
       at least one input waveguide;  
       an input slab waveguide optically coupled to the at least one input waveguide;  
       an arrayed waveguide grating optically coupled to the input slab waveguide; an output slab waveguide optically coupled to the input slab waveguide via the arrayed waveguide grating;  
       at least one output waveguide optically coupled to the output slab waveguide; and  
       at least one dendritic taper region optically coupled to at least one of the input slab waveguide and output slab waveguide; the dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein the trunk has a width that increases monotonically from the first end to the second end such that the increase in width does not exceed approximately 2 μm per approximately 1 μm traversed from the first end to the second end.  
     
     
       2. An optical wavelength router comprising: 
       at least one input waveguide;  
       an input slab waveguide optically coupled to the at least one input waveguide;  
       an arrayed waveguide grating optically coupled to the input slab waveguide;  
       an output slab waveguide optically coupled to the input slab waveguide via the arrayed waveguide grating;  
       at least one output waveguide optically coupled to the output slab waveguide; and  
       at least one dendritic taper region optically coupled to at least one of the input slab waveguide and output slab waveguide; the dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein the trunk has a width that decreases monotonically from the first end to the second end.  
     
     
       3. An optical wavelength router comprising: 
       at least one input waveguide;  
       an input slab waveguide optically coupled to the at least one input waveguide;  
       an arrayed waveguide grating optically coupled to the input slab waveguide;  
       an output slab waveguide optically coupled to the input slab waveguide via the arrayed waveguide grating;  
       at least one output waveguide optically coupled to the output slab waveguide; and  
       at least one dendritic taper region optically coupled to at least one of the input slab waveguide and output slab waveguide; the dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein the trunk has a width that varies non-monotonically.  
     
     
       4. An optical wavelength router comprising: 
       at least one input waveguide;  
       an input slab waveguide optically coupled to the at least one input waveguide;  
       an arrayed waveguide grating optically coupled to the input slab waveguide;  
       an output slab waveguide optically coupled to the input slab waveguide via the arrayed waveguide grating;  
       at least one output waveguide optically coupled to the output slab waveguide; and  
       at least one dendritic taper region optically coupled to at least one of the input slab waveguide and output slab waveguide; the dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein at least one branch of at least one dendritic taper is interconnected with at least one branch of another at least one dendritic taper.  
     
     
       5. An optical wavelength router comprising: 
       at least one input waveguide;  
       an input slab waveguide optically coupled to the at least one input waveguide;  
       an arrayed waveguide grating optically coupled to the input slab waveguide;  
       an output slab waveguide optically coupled to the input slab waveguide via the arrayed waveguide grating;  
       at least one output waveguide optically coupled to the output slab waveguide; and  
       at least one dendritic taper region optically coupled to at least one of the input slab waveguide and output slab waveguide; the dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein the branches increase in width with distance from the first end to the second end; wherein the branches define separation gaps therebetween; the separation gaps decreasing in width with distance from the first end to the second end.  
     
     
       6. An optical wavelength router comprising: 
       at least one input waveguide;  
       an input slab waveguide optically coupled to the at least one input waveguide;  
       an arrayed waveguide grating optically coupled to the input slab waveguide;  
       an output slab waveguide optically coupled to the input slab waveguide via the arrayed waveguide grating;  
       at least one output waveguide optically coupled to the output slab waveguide; and  
       at least one dendritic taper region optically coupled to at least one of the input slab waveguide and output slab waveguide; the dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein the branches increase in width with distance from the first end to the second end;  
       wherein the branches define separation gaps therebetween; each branch having an associated separation gap such that each branch and its associated separation gap have a combined width that is not a constant.  
     
     
       7. The optical wavelength router of  claim 1 ,  2 , or  3  wherein the at least one branch is curved. 
     
     
       8. The optical wavelength router of  claim 1 ,  2 ,  3 , or  4  wherein the branches increase in width with distance from the first end to the second end. 
     
     
       9. The optical wavelength router of  claim 8  wherein the branches define separation gaps therebetween; each of the separation gaps having a constant width. 
     
     
       10. The optical wavelength router of  claim 8  wherein the branched define separation gaps therebetween; each branch having an associated separation gap such that each branch and its associated separation gap have a combined width that is a constant. 
     
     
       11. The optical wavelength router of  claim 5  or  10  wherein the combined width of each branch and its associated separation gap has a constant value that is equal to 20 μm. 
     
     
       12. The optical wavelength router of  claim 1 ,  2 ,  3 , or  4  wherein the branches have a constant width with distance from the first end to the second end. 
     
     
       13. The optical wavelength router of  claim 12  wherein the branches define separation gaps therebetween; each of the separation gaps having a constant width. 
     
     
       14. The optical wavelength router of  claim 6  wherein the branches define separation gaps therebetween; the separation gaps decreasing in width with distance from the first end to the second end. 
     
     
       15. The optical wavelength router of  claim 1 ,  2 ,  3 ,  4 ,  5 , or  6  wherein the optical wavelength router is a multiplexer. 
     
     
       16. The optical wavelength router of  claim 1 ,  2 ,  3 ,  4 ,  5 , or  6  wherein the optical wavelength router is a demultiplexer. 
     
     
       17. An optical wavelength router comprising: 
       at least one input waveguide;  
       an input slab waveguide optically coupled to the at least one input waveguide;  
       an arrayed waveguide grating optically coupled to the input slab waveguide;  
       an output slab waveguide optically coupled to the input slab waveguide via the arrayed waveguide grating;  
       at least one output waveguide optically coupled to the output slab waveguide; and  
       at least one dendritic taper region optically coupled to at least one of the input slab waveguide and output slab waveguide; the dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein the at least one branch is substantially perpendicular to the trunk.  
     
     
       18. An optical wavelength router comprising: 
       at least one input waveguide;  
       an input slab waveguide optically coupled to the at least one input waveguide;  
       an arrayed waveguide grating optically coupled to the input slab waveguide;  
       an output slab waveguide optically coupled to the input slab waveguide via the arrayed waveguide grating;  
       at least one output waveguide optically coupled to the output slab waveguide; and  
       at least one dendritic taper region optically coupled to at least one of the input slab waveguide and output slab waveguide; the dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein one of the at least one dendritic taper region is an input dendritic taper region located between the at least one input waveguide and the input slab waveguide; the input dendritic taper region being optically coupled to the input slab waveguide and to the at least one input waveguide; the first end of the trunk of the input dendritic taper region being located distally from the input slab waveguide relative to the second end of the input dendritic taper region which is located proximately to input slab waveguide;  
       a first AWG dendritic taper region; the first AWG dendritic taper region being located between the input slab waveguide and the arrayed waveguide grating; the first AWG dendritic taper region being optically coupled to input slab waveguide and to the arrayed waveguide grating; the first end of the trunk of the first AWG dendritic taper region being located distally from the input slab waveguide relative to the second end of the trunk of the first AWG dendritic taper region which is located proximately to input slab waveguide.  
     
     
       19. The optical wavelength router of  claim 18  further including a second AWG dendritic taper region; the second AWG dendritic taper region being located between the output slab waveguide and the arrayed waveguide grating; the second AWG dendritic taper region being optically coupled to the output slab waveguide and to the arrayed waveguide grating; the first end of the trunk of the second AWG dendritic taper region being located distally from the output slab waveguide relative to the second end of the trunk of the second AWG dendritic taper region which is located proximately to the output slab waveguide. 
     
     
       20. The optical wavelength router of  claim 18  wherein the trunk of the input dendritic taper region has a width that increases monotonically from the first end to the second end such that the increase in width does not exceed approximately 2 μm per approximately 1 μm traversed from the first end to the second end. 
     
     
       21. The optical wavelength router of  claim 18  wherein the trunk of the input dendritic taper region has a width that decreases monotonically from the first end to the second end. 
     
     
       22. The optical wavelength router of  claim 18  wherein the trunk of the input dendritic taper region has a width that varies non-monotonically. 
     
     
       23. The optical wavelength router of  claim 18  wherein at least one branch of at least one dendritic taper is interconnected with at least one branch of another at least one dendritic taper. 
     
     
       24. The optical wavelength router of  claim 18  wherein at least one branch of at least one dendritic taper is not interconnected with at least one branch of another at least one dendritic taper. 
     
     
       25. The optical wavelength router of  claim 18  wherein the at least one branch of at least one dendritic taper is curved. 
     
     
       26. The optical wavelength router of  claim 18  wherein the at least one branch of at least one dendritic taper increases in width with distance from the first end to the second end. 
     
     
       27. The optical wavelength router of  claim 26  wherein the branches define separation gaps therebetween; each of the separation gaps having a constant width. 
     
     
       28. The optical wavelength router of  claim 18  wherein the at least one branch increases in width with distance from the first end to the second end; 
       wherein the branches define separation gaps therebetween; the separation gaps decreasing in width with distance from the first end to the second end.  
     
     
       29. The optical wavelength router of  claim 26  wherein the branches define separation gaps therebetween; each branch having an associated separation gap such that each branch and its associated separation gap have a combined width that is a constant. 
     
     
       30. The optical wavelength router of  claim 18  wherein the at least one branch increases in width with distance from the first end to the second end; 
       wherein the combined width of each branch and its associated separation gap has a constant value that is equal to 20 μm.  
     
     
       31. The optical wavelength router of  claim 18  wherein the at least one branch increases in width with distance from the first end to the second end, and wherein the branches define separation gaps therebetween; each branch having an associated separation gap such that each branch and its associated separation gap have a combined width that is not a constant. 
     
     
       32. The optical wavelength router of  claim 18  wherein the branches have a constant width with distance from the first end to the second end wherein the branches define separation gaps therebetween; the separation gaps decreasing in width with distance from the first end to the second end. 
     
     
       33. The optical wavelength router of  claim 18  wherein the at least one branch is substantially perpendicular to the trunk. 
     
     
       34. The optical wavelength router of  claim 18  wherein the at least one branch is not perpendicular to the trunk. 
     
     
       35. The optical wavelength router of  claim 18  wherein the at least one branch has an index of refraction that is substantially the same as an index of refraction of the trunk. 
     
     
       36. An optical wavelength router comprising: 
       at least one input waveguide;  
       an input slab waveguide optically coupled to the at least one input waveguide;  
       an arrayed waveguide grating optically coupled to the input slab waveguide;  
       an output slab waveguide optically coupled to the input slab waveguide via the arrayed waveguide grating;  
       at least one output waveguide optically coupled to the output slab waveguide; and  
       at least one dendritic taper region optically coupled to at least one of the input slab waveguide and output slab waveguide; the dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein one of the at least one dendritic taper region is an output dendritic taper region located between the output slab waveguide and the at least one output waveguide; the output dendritic taper region being optically coupled to the output slab waveguide and to the at least one output waveguide; the first end of the trunk of the output dendritic taper region being located distally from the output slab waveguide relative to the second end of the output dendritic taper region which is located proximately to the output slab waveguide;  
       an input dendritic taper region located between the at least one input waveguide and the input slab waveguide; the input dendritic taper region being optically coupled to the input slab waveguide and to the at least one input waveguide; the first end of the trunk of the input dendritic taper region being located distally from the input slab waveguide relative to the second end of the input dendritic taper region which is located proximately to the input slab waveguide;  
       a first AWG dendritic taper region; the first AWG dendritic taper region being located between the input slab waveguide and the arrayed waveguide grating; the first AWG dendritic taper region being optically coupled to the input slab waveguide and to the arrayed waveguide grating; the first end of the trunk of the first AWG dendritic taper region being located distally from the input slab waveguide relative to the second end of the trunk of the first AWG dendritic taper region which is located proximately to the input slab waveguide.  
     
     
       37. An optical wavelength router comprising: 
       at least one input waveguide;  
       an input slab waveguide optically coupled to the at least one input waveguide;  
       an arrayed waveguide grating optically coupled to the input slab waveguide;  
       an output slab waveguide optically coupled to the input slab waveguide via the arrayed waveguide grating;  
       at least one output waveguide optically coupled to the output slab waveguide; and  
       at least one dendritic taper region optically coupled to at least one of the input slab 54 waveguide and output slab waveguide; the dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein one of the at least one dendritic taper region is an output dendritic taper region located between the output slab waveguide and the at least one output waveguide; the output dendritic taper region being optically coupled to the output slab waveguide and to the at least one output waveguide; the first end of the trunk of the output dendritic taper region being located distally from the output slab waveguide relative to the second end of the output dendritic taper region which is located proximately to the output slab waveguide;  
       a first AWG dendritic taper region; the first AWG dendritic taper region being located between the input slab waveguide and the arrayed waveguide grating; the first AWG dendritic taper region being optically coupled to the input slab waveguide and to the arrayed waveguide grating; the first end of the trunk of the first AWG dendritic taper region being located distally from the input slab waveguide relative to the second end of the trunk of the first AWG dendritic taper region which is located proximately to the input slab waveguide;  
       a second AWG dendritic taper region; the second AWG dendritic taper region being located between the output slab waveguide and the arrayed waveguide grating; the second AWG dendritic taper region being optically coupled to the output slab waveguide and to the arrayed waveguide grating; the first end of the trunk of the second AWG dendritic taper region being located distally from the output slab waveguide relative to the second end of the trunk of the second AWG dendritic taper region which is located proximately to the output slab waveguide.  
     
     
       38. The optical wavelength router of  claim 36  further including a second AWG dendritic taper region; the second AWG dendritic taper region being located between the output slab waveguide and the arrayed waveguide grating; the second AWG dendritic taper region being optically coupled to the output slab waveguide and to the arrayed waveguide grating; the first end of the trunk of the second AWG dendritic taper region being located distally from the output slab waveguide relative to the second end of the trunk of the second AWG dendritic taper region which is located proximately to the output slab waveguide. 
     
     
       39. The optical wavelength router of  claim 36  or  37  wherein the trunk has a width that increases monotonically from the first end to the second end such that the increase in width does not exceed approximately 2 μm per approximately 1 μm traversed from the first end to the second end. 
     
     
       40. The optical wavelength router of  claim 36  or  37  wherein at least one branch of at least one dendritic taper is interconnected with at least one branch of another at least one dendritic taper. 
     
     
       41. The optical wavelength router of  claim 36  or  37  wherein the at least one branch is substantially perpendicular to the trunk. 
     
     
       42. An optical wavelength router comprising: 
       at least one input waveguide;  
       an slab waveguide optically coupled to the at least one input waveguide; the slab waveguide including an integrated reflection grating;  
       at least one output waveguide optically coupled to the slab waveguide; and  
       at least one dendritic taper region including at least one dendritic taper; the dendritic taper including a trunk having a first end and a second end; the dendritic taper including at least one branch optically coupled to the trunk;  
       wherein the trunk has a width that increases monotonically from the first end to the second end such that the increase in width does not exceed approximately 2 μm per approximately 1 μm traversed from the first end to the second end.  
     
     
       43. The optical wavelength router of  claim 42  wherein at least one branch of at least one dendritic taper is interconnected with at least one branch of another at least one dendritic taper. 
     
     
       44. The optical wavelength router of  claim 42  wherein at least one branch of at least one dendritic taper is not interconnected with at least one branch of another at least one dendritic taper. 
     
     
       45. The optical wavelength router of  claim 42  wherein the at least one branch is curved. 
     
     
       46. The optical wavelength router of  claim 42  wherein the branches increase in width with distance from the first end to the second end. 
     
     
       47. The optical wavelength router of  claim 46  wherein the branches define separation gaps therebetween; each of the separation gaps having a constant width. 
     
     
       48. The optical wavelength router of  claim 46  wherein the branches define separation gaps therebetween; the separation gaps decreasing in width with distance from the first end to the second end. 
     
     
       49. The optical wavelength router of  claim 46  wherein the branches define separation gaps therebetween; each branch having an associated separation gap such that each branch and its associated separation gap have a combined width that is a constant. 
     
     
       50. The optical wavelength router of  claim 49  wherein the combined width of each branch and its associated separation gap is 20 μm. 
     
     
       51. The optical wavelength router of  claim 46  wherein the branches define separation gaps therebetween; each branch having an associated separation gap such that each branch and its associated separation gap have a combined width that is not a constant. 
     
     
       52. The optical wavelength router of  claim 42  wherein the branches have a constant width with distance from the first end to the second end. 
     
     
       53. The optical wavelength router of  claim 52  wherein the branches define separation gaps therebetween; each of the separation gaps having a constant width. 
     
     
       54. The optical wavelength router of  claim 52  wherein the branches define separation gaps therebetween; the separation gaps decreasing in width with distance from the first end to the second end. 
     
     
       55. The optical wavelength router of  claim 42  wherein the optical wavelength router is a multiplexer. 
     
     
       56. The optical wavelength router of  claim 42  wherein the optical wavelength router is a demultiplexer.